Modern firearms, including those employed in military and law enforcement applications, often include various accessories to assist the shooter. Such devices may be mounted directly to the firearm or indirectly on a mount associated with the firearm. Conventional mounts include securing accessories to the firearm with a Picatinny rail. A Picatinny rail is a bracket used on firearms in order to provide a standardized mounting platform for accessories and attachments, such as scopes. These rails generally include a single rail extending along the upper surface of the firearm and typically extend at least over the receiver and barrel portions of the firearm. The rail comprises a series of ridges with a T-shaped cross-section interspersed with flat “spacing slots”. Accessories are mounted by sliding them on from one end or the other, by means of a clamp, or onto the slots between the raised sections.
A single rail system has been effective for its intended purpose for traditional rifle stocks. It is desirable, however, to provide modular, user configurable tactical firearms that can be adapted to meet a variety of environmental, operational and/or user preference requirements. An example of a prior art modular firearm is disclosed in U.S. Pat. No. 7,802,392 B2. A preferable configurable, tactical firearm is Applicants' modular chassis weapons platform set forth in U.S. Pat. No. 8,429,844 (U.S. application Ser. No. 13/184,501), the disclosure of which is hereby incorporated by reference. Each of these modular weapons platforms employs a single rail assembly. Although a single rail assembly effectively achieves its intended purposes, such as effective accessory mounting for a modular weapons platform, it does not provide configurable or interchangeable features akin to the desirable features of the modular weapons platform upon which it is mounted. Prior art single rail systems do not facilitate the additional felixibility of using a modular weapons platform with a modular rail assembly according to the present invention.